In daily life, for exactly identifying environment and directions in the dark, illumination devices have already been sorts of indispensable tools. In most existed illumination devices, it is necessary for the illumination devices to assemble the lighting elements to a fixed type of light fixtures, and then the illumination devices can provide the function of illumination after being driven by proper power. While, such illumination devices can be used in the way of fix-type illumination only, but cannot be used in portable-type or versatile-type of illumination.
After that, for making these illumination device being portable, the lighting elements are assembled to a portable shell to be a portable illumination device, such as a flashlight, a headlight, and so on. Although the portable illumination devices bring the convenience of carrying, they are just able to be used in specified usages, such as that the flashlights are used in the field of hand-held illumination, and the headlights are used to provide illumination by fixing the head strap to the head or the waist portion of the human body.
Since these portable illumination devices can just be used in specified usages, but cannot be fixed to different kinds of fixtures, thus an illumination cell capable of attaching to many different kinds of fixtures is developed. Following up, we will provide simple descriptions of the structure of the illumination cell.
Please refer to FIG. 1, which illustrates a sectional view of a conventional illumination cell. As shown in FIG. 1, an illumination cell 1 comprises a shell 11, an illumination opening 12, a light-transmissible element 13, a circuit board 14, a battery 15, a light emitting diode (LED) 16, and an adhesive element 17. The illumination opening 12 is formed on the shell 11. The circuit board 14 is arranged within the shell 11, and arranged with a supply circuit (not shown in FIG. 1). The battery 15 and the LED 16 are electrically connected with the supply circuit. The adhesive element 17 is attached on an outer surface of the shell 11 opposite to the illumination opening 12. Besides, a battery lid (not shown in FIG. 1) also can be provided to cover a battery opening (not shown in FIG. 1) formed on the shell 11.
When a user uses the illumination cell 1, the user can attach the illumination cell 1 to the surface of a fixture, and make the battery 15 supply power to the LED 16 via the supply circuit arranged on the circuit board 14, so as to drive the LED 16 projecting an illumination light beam IL0. Hereafter, the illumination light beam IL0 can be projected out from the illumination cell 1 through the light-transmissible element 13 to provide a portable-type illumination to an external environment. When said power supplied by the battery is insufficient to drive the LED 16 normally projecting the illumination light beam IL0, the user can open the battery lid to replace the battery 15 with another one.
In the above application, although the development of the illumination cell 11 has successfully transferred the portable-type illumination to the versatile-type illumination, there are still three problems existing as follows.
Firstly, since the battery 15 is not a rechargeable battery, so that the battery 15 cannot be recharged. Even though, the battery is a rechargeable battery, the circuit board 14 is not disposed with a charging circuit. Therefore, it is still not able to directly charge the battery 15 when the battery is still assembled within the illumination cell 1.
Secondly, even though, the battery can be charged by an external charging module, an external power source with a charging loop is still a must. Once, a plurality of illumination cells 1 are used, it will be necessary to connect a plurality of charging loops, or additionally connect with at least one power distributor.
Thirdly, under the processes of charging, if the amount of the charging loops are not enough with respect to the amount of the illumination cells 1, the illumination cells not connected to any charging loop cannot be charged. Certainly, the illumination cells have insufficient power so as to not provide the specified illumination function to the external environment.